Synthetic polymeric materials, such as polyethylene terephthalate and polypropylene, are widely used in injection stretch blow molding manufacturing of containers, such as bottles and jars, for a variety of commercial end-uses ranging from medical containers to food containers. While articles constructed from synthetic polymeric materials have widespread utility, these materials tend to degrade slowly, if at all, in a natural environment. In response to environmental concerns, interest in the production and utility of more readily biodegradable polymeric materials comprising polylactic acid, a biodegradable polymer, has been increasing. These materials, also known as “green materials”, may undergo accelerated degradation in a natural environment. The utility of these biodegradable polymeric materials is often limited by their poor mechanical and/or physical properties.
Attempts have been made to utilize polylactic acid for injection stretch blow molding (ISBM) applications. However, PLA is known to be brittle and exhibit low toughness, which results in unsatisfactorily low impact strength ISBM articles, particularly at cold temperatures. As ISBM articles are good candidates to contain refrigerated food and beverages, cold temperature drop impact strength is a desirable characteristic. Blends of PLA with elastomeric materials or other impact modifying polymers have been proposed, however due to poor processability and/or undesirable mechanical properties (e.g., low top load strength, low bumper compression strength), previous blends have not been used successfully in ISBM applications requiring impact strength and production efficiency. Therefore, a need exists for a biodegradable blend suitable for ISBM production of articles having improved drop impact strength, thus providing an environmentally friendly alternative to synthetic polymeric materials.